"It was three o'clock in the morning when the fighting got too bad," said Abu Mohammed, a father of two. "I was ready. I had kept our ID documents in the car so we could leave quickly. This is the seventh time my family has been displaced because of war."

His family duly abandoned their home and possessions all over again.

A bloody struggle for control of Iraq is taking place on two fronts, each with a starkly different balance of power.

Along the Euphrates Valley and across the desert of Anbar province, Isil fighters are still on the march. This is where they launched their new assault on Ramadi, a provincial capital 100 miles west of Baghdad.

On the other front, which slices across the Tigris Valley, the terrorists have been forced on to the defensive. A counter-attack by the Baghdad government has expelled Isil from all but a few pockets ofSaddam Hussein's home city of Tikrit.

A soldier stands guard atop his armored vehicle at the Southern Stadium neighborhood of Ramadi, Iraq

This victory allowed government forces to carve a corridor of control stretching northwards for 120 miles from Baghdad to Tikrit. It also allowed them to produce the body of Izzat Ibrahim al-Douri, a veteran pillar of Saddam's regime, who isbelieved to have been killed on Friday while fighting alongside Isil.

On balance, the jihadists have lost more ground along the Tigris than they have gained beside the Euphrates. A Pentagon assessment released last Tuesday concluded that Isil had been driven from at least a quarter of the area of Iraq that it captured last year.

"Isil is no longer the dominant force in roughly 25 to 30 per cent of the populated areas of Iraqi territory where it once had complete freedom of movement," said the Pentagon statement. This suggests that Isil has lost between 5,000 and 6,500 square miles.

After the recapture of Tikrit, the next target of the Tigris counter-offensive will be Mosul, the biggest city in northern Iraq with a population of about 1.5 million.

In February, a spokesman for US Central Command said that America and its allies would train 25,000 Iraqi troops to recapture Mosul as early as May. But that plan now lies in tatters. The counter-attack along the Tigris has also exposed the frailty of Iraq's security forces.

Last summer, the national army collapsed in the face of Isil's challenge, with four divisions simply disintegrating. Today, the army remains too weak to mount a counter-offensive without help.

The backbone of the assault that recaptured Tikrit was provided by the Popular Mobilisation Force, a loose coalition of Shia militias and fighters recruited from local Sunni tribes. Of the 24,000 troops that wrested back Tikrit, 20,000 were Shia militiamen, according to US officials. Only 3,000 were from the Iraqi army and the remaining 1,000 were from Sunni tribes.

Displaced Sunni people, who fled the violence in the city of Ramadi, arrive at the outskirts of Baghdad

The Shia militias are, in turn, equipped and largely controlled by neighbouring Iran. Gen Qassem Suleimani, the commander of the Quds Force of the Iranian Revolutionary Guard, no longer troubles to hide his responsibility for the campaign against Isil. On the contrary, he has been photographed visiting his victorious troops in Tikrit.

But the population of this area is overwhelmingly Sunni. Local people may not welcome their "liberation" by Shia militia fighters, especially if reprisals or atrocities follow.

"The government is so dependent on Shia militias that they are playing a role in most front lines," said Aymen al-Tammimi, from the Middle East Forum, a think tank.

Mobilising Shia forces to retake largely Sunni areas is fraught with risk. When Isil was expelled from Tikrit, some militia fighters seized the opportunity to loot homes that were abandoned during the fighting. Video footage showed others attaching a corpse to a car and dragging it through the streets.

The potential for revenge was reduced by the fact that most of Tikrit's inhabitants had fled. But the same may not be true elsewhere. "Tikrit was mostly empty," said Mr Tammimi. "But Ramadi and Mosul are still inhabited by thousands of Sunni Muslim residents. There the revenge killings could be brutal."

American officials are adamant that the national army, not Shia militias, will lead the operation to retake Mosul. But there is precious little chance of the required force being ready by May – or for months afterwards.

That is partly explained by Isil's recent advance along the Euphrates front, where Iraqi troops are bogged down in a war of attrition.

Residents told the Telegraph that Isil seized parts of Ramadi on Wednesday. "We woke to explosions and shooting," said Abu Mohammed, who fled with 12 other members of his family. "We heard that the Iraq army forces were retreating from our neighbourhood as Isil attacked. Everyone in the neighbourhood was escaping."

Iraqi security troops head to Ramadi on the orders of Prime Minister Haider al-Abadi to re-enforce troops there

Some left by car, others on foot. The roads out of the Ramadi were packed with civilians. But army checkpoints slowed the progress of the fugitives, forcing them to wait for hours at every one.

"It was so hot in the sun. Some elderly people fainted from the stress and exhaustion. I saw one women give birth on the road," said Abu Mohammed, who used the pseudonym "father of Mohammed" for his own protection.

Sattar Nowruz, from the ministry of migration and the displaced, said that 2,000 families had fled Ramadi for the southern and western suburbs of Baghdad.

Abu Mohammed added that people in his neighbourhood feared becoming targets for Isil, although they are Sunni Muslims. "They had not managed to enter our district for the last year because the people there did not welcome them. So they issued a fatwa, a religious decree, declaring us all infidels," he explained.

Whenever the jihadists capture an area, they first purge it of anyone linked to the Iraqi government. "Even just giving food to the soldiers is enough to get you targeted," said Abu Mohammed. "They have lists of names of people they want. They blow up or burn the homes of officials and murder them and their families if they can find them."

Life for civilians in Isil-held territory is becoming steadily harder. In Mosul, residents often have no electricity while medical supplies are scarce.

Documents drawn up by the jihadists show the new laws imposed on the civilian population: clothes shops have been formally banned from selling dresses or displaying the faces of their manikins. Certain departments of Mosul University, including arts and archaeology, have been shut.

As the war continues, the line between Shia militias and government forces is increasingly blurred. Mohammed al-Ghabban, the new interior minister, is also a member of the Badr Brigade, an Iranian-sponsored armed group.

Meanwhile, ordinary civilians are suffering most of all. At least 14,000 people have been killed in the past 12 months, according to the United Nations.

Whatever the balance of forces on the two fronts, the latest round of the battle for Iraq has inflicted the bloodiest year the country has endured for almost a decade.